Graduate School of Integrated Arts and Sciences, Hiroshima University, Hiroshima, Japan.
Japan Society for the Promotion of Science, Tokyo, Japan.
Am J Clin Nutr. 2019 Jul 1;110(1):41-52. doi: 10.1093/ajcn/nqy346.
Skipping breakfast has become a common trend that may lead to obesity and type 2 diabetes. Previous studies, which imposed a single incidence of breakfast skipping, did not observe any decrease in 24-h energy expenditure. Furthermore, the effects of breakfast skipping on diurnal blood glucose profiles over 24 h are contradictory.
The aim of this study was to clarify the influence of 6 consecutive days of breakfast skipping and sedentary behavior on energy metabolism and glycemic control.
Ten young men participated in 2 trials (with or without breakfast) that lasted for 6 consecutive days, and the 2 trials were conducted 1 wk apart with a repeated-measures design. During the meal intervention, each subject's blood glucose was measured using the continuous glucose monitoring system. If breakfast was skipped, subjects ate large meals at lunch and dinner such that the 24-h energy intake was identical to that of the 3-meal condition. At 2200 on the fifth day, the subjects entered a room-sized respiratory chamber, where they remained for 33 h, and were instructed to carry out sedentary behavior.
The glucose levels were similar between the 2 meal conditions during the first 5 d of meal intervention, but the blood glucose at 2300 was higher in the breakfast-skipping condition than in the 3-meal condition. Breakfast skipping elevated postprandial glycemic response after lunch on the first day of meal intervention. On the sixth day, there were no significant differences in 24-h energy expenditure and substrate oxidation. When subjects remained in a metabolic chamber, the level of physical activity significantly decreased, glycemic stability slightly deteriorated, and mean blood glucose over 24 h was higher in the breakfast-skipping trial than in the 3-meal trial.
Sedentary lifestyle and repeated breakfast skipping caused abnormal glucose fluctuations, whereas 24-h energy metabolism remained unaffected. Clinical Trial Registry: This trial was registered at http://www.umin.ac.jp/english/ as UMIN000032346.
不吃早餐已成为一种普遍趋势，可能导致肥胖和 2 型糖尿病。之前的研究仅观察到一次不吃早餐，并未发现 24 小时能量消耗有任何降低。此外，关于不吃早餐对 24 小时日间血糖谱的影响存在矛盾。
本研究旨在阐明连续 6 天不吃早餐和久坐行为对能量代谢和血糖控制的影响。
10 名年轻男性参与了 2 项试验（吃早餐和不吃早餐），每项试验持续 6 天，且 2 项试验以重复测量设计相隔 1 周进行。在膳食干预期间，使用连续血糖监测系统测量每位受试者的血糖。如果不吃早餐，受试者会在午餐和晚餐时吃大餐，以使 24 小时能量摄入与 3 餐条件相同。在第 5 天 22：00，受试者进入一个房间大小的呼吸室，在那里停留 33 小时，并被要求保持久坐行为。
在膳食干预的前 5 天，2 种膳食条件下的血糖水平相似，但在不吃早餐条件下，23：00 的血糖水平高于 3 餐条件。不吃早餐会增加第 1 天膳食干预后午餐后的餐后血糖反应。第 6 天，24 小时能量消耗和底物氧化没有显著差异。当受试者留在代谢室内时，体力活动水平显著降低，血糖稳定性略有恶化，且在不吃早餐试验中，24 小时平均血糖高于 3 餐试验。
久坐的生活方式和反复不吃早餐会导致血糖波动异常，而 24 小时能量代谢不受影响。临床试验注册：该试验在 http://www.umin.ac.jp/english/ 注册，注册号为 UMIN000032346。
